Abstract ? Project 2 ? Biomarker Project The MIDUS Biomarker Project has led to widespread engagement from the scientific community: 122 publications have been generated, 47% of which appeared in 2014/15. The goal of this project is to build on this momentum by collecting longitudinal data (9-10 years later) on the baseline biomarker sample, 90% of whom recently returned for the MIDUS 3 survey assessments. We will repeat the comprehensive battery of initial biomarkers (neuroendocrine, inflammatory, glucose metabolism, cardiovascular, musculoskeletal) plus add new measures in 5 targeted areas (ankle-brachial index, HDL function, body impedance, gait analysis, expanded cytokine panel). This revision details numerous specific hypotheses to be tested with the new biomarker data, most of which build systematically on key findings generated from the baseline data. Our design allows for the investigation of multiple pathways through which 3 waves of sociodemographic data and 3 waves of psychosocial data can be combined to predict cross-time change in biological risk profiles. Negative pathways combine cumulative vulnerability factors (e.g., persistently low SES + chronically high or incrementing depressive profiles) to predict worsening biological risk across time. Positive pathways combine cumulative advantage factors (e.g., majority status + persistently high social relational ties) to predict maintenance or improvement in biological regulation across time. Most novel are resilient pathways that combine vulnerability and protective factors (e.g., persistently low SES + persistently high well-being) to predict healthy cross-time biology and maintenance of functional capacities. The MIDUS Biomarker Project enjoys three key features that distinguish it from other U.S. studies. First, it provides longitudinal biological data that span change over 10 years in a population-representative sample, which included adults aged 25 to 74 at baseline. Second, the biomarkers collected in the project are far richer than any other U.S. population-based sample. Third, the extensive survey data of MIDUS ? now encompassing over 20 years of prospective information on socioeconomic, psychosocial, and behavioral aspects of participants' lives -- provide unique opportunities for testing how these factors combine to account for who has maintained healthy biological regulation and functional health across time, while others have shifted toward clinically significant biological risk, or moved from pre-disease to disease states. The Biomarker Project has a history of over 15 years of successful collaboration among team leaders -- Carol Ryff (University of Wisconsin-Madison), Teresa Seeman (University of California-Los Angeles), and Maxine Weinstein (Georgetown University). The protocols at each site are well established, and the respective site teams have strong track records of successful recruitment and testing.